- Color: colorless, light yellow, brownish. Very rare varieties: red, blue, green, yellow.
- Hardness: 10
- Refractive index: 2.42
- Density: 3.52
- Chemical composition: C
- Crystal structure: cubic
- Origins: Southern and central Africa, Russia, Canada, Australia, India, Brazil.
The most expensive gemstone with unique physical and optical properties. The most valuable diamonds are either absolutely colorless or 'fancy diamonds' with an intense yellow, red, green or blue hue. Diamonds are generally not treated, however rare, colored fancy diamonds are often irradiated and heated to intensify their colors.